Boom bases and sandbags

RonaldBeal

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Joined
Jan 24, 2004
Location
TN
Anyone have a standard, regulation, or rule of thumb for how much sandbag counterweight is needed for boom bases and/or truss towers.

(We can calculate CG, tipping angle and force required to topple at different heights but how much is safe/unsafe?)

Backstory... a local "technical person" is insisting that every boom base needs a 25 to 1 weight ratio to be safe (so 500 pounds of sandbags to make a 20 pound S4 safe)
His "formula" does not take into account height, off axis weight etc... so looking for something proper and not just a WAG or "this is how we have always done it
 

derekleffew

Resident Curmudgeon
Senior Team
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Las Vegas, NV, USA
ANSI E1.15 - 2006 (R2021)
Entertainment Technology - Recommended Practices and Guidelines for the Assembly and Use of Theatrical Boom & Base Assemblies
ANSI E1.15 - 2006 (R2021) is a reaffirmation of the 2006 standard. It gives advice on boom and base assemblies, simple ground-support devices for lighting equipment and accessories. If the assembly is tall, not plumb, loaded unevenly, or likely to get run into by stage wagons or performers, there is substantial risk. This document offers advice to lower or eliminate that risk.
 

Amiers

Renting to Corporate One Fixture at a Time.
Joined
May 28, 2009
Location
Phoenix, Az
Anyone have a standard, regulation, or rule of thumb for how much sandbag counterweight is needed for boom bases and/or truss towers.

(We can calculate CG, tipping angle and force required to topple at different heights but how much is safe/unsafe?)

Backstory... a local "technical person" is insisting that every boom base needs a 25 to 1 weight ratio to be safe (so 500 pounds of sandbags to make a 20 pound S4 safe)
His "formula" does not take into account height, off axis weight etc... so looking for something proper and not just a WAG or "this is how we have always done it
That’s a lot of sand for one fixture. I think his math might be off.
 

ACTSTech

Well-Known Member
Joined
Nov 13, 2019
Location
USA
Isn't the calculation "If some is good, more is better!"?
This is the standard rule of thumb for lighting and sound, especially for divas. Louder=better, brighter=better.

Hanging lights I usually hope for 10:1, meaning if the light weighs 75lbs I'd like the truss to support 750, especially for movers. But for something sitting on the stage deck, 25:1 seems a hair over.

The problem is the ESTA specifications: ANSI E1.15 – 2006 (R2021) Qualified Person: A person who, by possession of a recognized degree or certification of professional standing, or who by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve or resolve problems relating to the subject matter or work.

Who determines what's qualifying?
 

MNicolai

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Premium Member
Fight Leukemia
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Mar 30, 2008
Location
Sarasota, FL
Who determines what's qualifying?
ESTA's been sliding similar language into NFPA code. It's their way of suggesting the person should be ETCP-certified without name dropping themselves as the provider of that certification.
 
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